It is known to control hydraulic engines in a hydraulic system by means of control valves or sequence valves, which are coupled in between the engines and the respective pumps. A sequence valve to be used in this connection has a pressure-controlled sliding part with a return spring and in a starting position defines a first cavity, which cavity is connected with a tank and the hydraulic system, and in a second, pressurised position closes off the connection with the tank. The cavity is connected to a second cavity via a channel in the sliding part, and the second cavity is adapted to be connected with a pump and is positioned on the same side of the sliding part as the spring. When starting the pump, oil is led to the above-mentioned cavity which both directs oil to the engines and to the tank into a pressure means which is connected with the pump and which brings the sliding part to its pressurised position.
Known sequence valves have required the use of throttle able to withstand up to approximately 200 bar, which entails that the throttle must be relatively narrow and thus easily clogs up.